diff options
| -rw-r--r-- | fs/crypto/hooks.c | 15 | ||||
| -rw-r--r-- | fs/ext4/namei.c | 1 | ||||
| -rw-r--r-- | fs/ext4/super.c | 1 | ||||
| -rw-r--r-- | fs/f2fs/namei.c | 1 | ||||
| -rw-r--r-- | fs/f2fs/super.c | 1 | ||||
| -rw-r--r-- | fs/libfs.c | 102 | ||||
| -rw-r--r-- | fs/overlayfs/params.c | 14 | ||||
| -rw-r--r-- | fs/ubifs/dir.c | 1 | ||||
| -rw-r--r-- | fs/ubifs/super.c | 1 | ||||
| -rw-r--r-- | include/linux/fs.h | 11 | ||||
| -rw-r--r-- | include/linux/fscrypt.h | 66 |
11 files changed, 128 insertions, 86 deletions
diff --git a/fs/crypto/hooks.c b/fs/crypto/hooks.c index 52504dd478d3..104771c3d3f6 100644 --- a/fs/crypto/hooks.c +++ b/fs/crypto/hooks.c @@ -102,11 +102,8 @@ int __fscrypt_prepare_lookup(struct inode *dir, struct dentry *dentry, if (err && err != -ENOENT) return err; - if (fname->is_nokey_name) { - spin_lock(&dentry->d_lock); - dentry->d_flags |= DCACHE_NOKEY_NAME; - spin_unlock(&dentry->d_lock); - } + fscrypt_prepare_dentry(dentry, fname->is_nokey_name); + return err; } EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup); @@ -131,12 +128,10 @@ EXPORT_SYMBOL_GPL(__fscrypt_prepare_lookup); int fscrypt_prepare_lookup_partial(struct inode *dir, struct dentry *dentry) { int err = fscrypt_get_encryption_info(dir, true); + bool is_nokey_name = (!err && !fscrypt_has_encryption_key(dir)); + + fscrypt_prepare_dentry(dentry, is_nokey_name); - if (!err && !fscrypt_has_encryption_key(dir)) { - spin_lock(&dentry->d_lock); - dentry->d_flags |= DCACHE_NOKEY_NAME; - spin_unlock(&dentry->d_lock); - } return err; } EXPORT_SYMBOL_GPL(fscrypt_prepare_lookup_partial); diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 05b647e6bc19..5e4f65c14dfb 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1762,7 +1762,6 @@ static struct buffer_head *ext4_lookup_entry(struct inode *dir, struct buffer_head *bh; err = ext4_fname_prepare_lookup(dir, dentry, &fname); - generic_set_encrypted_ci_d_ops(dentry); if (err == -ENOENT) return NULL; if (err) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index dcba0f85dfe2..215b4614eb15 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -5484,6 +5484,7 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb) goto failed_mount4; } + generic_set_sb_d_ops(sb); sb->s_root = d_make_root(root); if (!sb->s_root) { ext4_msg(sb, KERN_ERR, "get root dentry failed"); diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c index b3bb815fc6aa..f7f63a567d86 100644 --- a/fs/f2fs/namei.c +++ b/fs/f2fs/namei.c @@ -531,7 +531,6 @@ static struct dentry *f2fs_lookup(struct inode *dir, struct dentry *dentry, } err = f2fs_prepare_lookup(dir, dentry, &fname); - generic_set_encrypted_ci_d_ops(dentry); if (err == -ENOENT) goto out_splice; if (err) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index d45ab0992ae5..8d9bd880ffd8 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -4660,6 +4660,7 @@ try_onemore: goto free_node_inode; } + generic_set_sb_d_ops(sb); sb->s_root = d_make_root(root); /* allocate root dentry */ if (!sb->s_root) { err = -ENOMEM; diff --git a/fs/libfs.c b/fs/libfs.c index 6182e2b03094..78c71a9e2e18 100644 --- a/fs/libfs.c +++ b/fs/libfs.c @@ -1738,16 +1738,28 @@ bool is_empty_dir_inode(struct inode *inode) static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, const char *str, const struct qstr *name) { - const struct dentry *parent = READ_ONCE(dentry->d_parent); - const struct inode *dir = READ_ONCE(parent->d_inode); - const struct super_block *sb = dentry->d_sb; - const struct unicode_map *um = sb->s_encoding; - struct qstr qstr = QSTR_INIT(str, len); + const struct dentry *parent; + const struct inode *dir; char strbuf[DNAME_INLINE_LEN]; - int ret; + struct qstr qstr; + + /* + * Attempt a case-sensitive match first. It is cheaper and + * should cover most lookups, including all the sane + * applications that expect a case-sensitive filesystem. + * + * This comparison is safe under RCU because the caller + * guarantees the consistency between str and len. See + * __d_lookup_rcu_op_compare() for details. + */ + if (len == name->len && !memcmp(str, name->name, len)) + return 0; + parent = READ_ONCE(dentry->d_parent); + dir = READ_ONCE(parent->d_inode); if (!dir || !IS_CASEFOLDED(dir)) - goto fallback; + return 1; + /* * If the dentry name is stored in-line, then it may be concurrently * modified by a rename. If this happens, the VFS will eventually retry @@ -1758,20 +1770,14 @@ static int generic_ci_d_compare(const struct dentry *dentry, unsigned int len, if (len <= DNAME_INLINE_LEN - 1) { memcpy(strbuf, str, len); strbuf[len] = 0; - qstr.name = strbuf; + str = strbuf; /* prevent compiler from optimizing out the temporary buffer */ barrier(); } - ret = utf8_strncasecmp(um, name, &qstr); - if (ret >= 0) - return ret; + qstr.len = len; + qstr.name = str; - if (sb_has_strict_encoding(sb)) - return -EINVAL; -fallback: - if (len != name->len) - return 1; - return !!memcmp(str, name->name, len); + return utf8_strncasecmp(dentry->d_sb->s_encoding, name, &qstr); } /** @@ -1800,73 +1806,45 @@ static int generic_ci_d_hash(const struct dentry *dentry, struct qstr *str) static const struct dentry_operations generic_ci_dentry_ops = { .d_hash = generic_ci_d_hash, .d_compare = generic_ci_d_compare, -}; -#endif - #ifdef CONFIG_FS_ENCRYPTION -static const struct dentry_operations generic_encrypted_dentry_ops = { .d_revalidate = fscrypt_d_revalidate, +#endif }; #endif -#if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE) -static const struct dentry_operations generic_encrypted_ci_dentry_ops = { - .d_hash = generic_ci_d_hash, - .d_compare = generic_ci_d_compare, +#ifdef CONFIG_FS_ENCRYPTION +static const struct dentry_operations generic_encrypted_dentry_ops = { .d_revalidate = fscrypt_d_revalidate, }; #endif /** - * generic_set_encrypted_ci_d_ops - helper for setting d_ops for given dentry - * @dentry: dentry to set ops on - * - * Casefolded directories need d_hash and d_compare set, so that the dentries - * contained in them are handled case-insensitively. Note that these operations - * are needed on the parent directory rather than on the dentries in it, and - * while the casefolding flag can be toggled on and off on an empty directory, - * dentry_operations can't be changed later. As a result, if the filesystem has - * casefolding support enabled at all, we have to give all dentries the - * casefolding operations even if their inode doesn't have the casefolding flag - * currently (and thus the casefolding ops would be no-ops for now). - * - * Encryption works differently in that the only dentry operation it needs is - * d_revalidate, which it only needs on dentries that have the no-key name flag. - * The no-key flag can't be set "later", so we don't have to worry about that. + * generic_set_sb_d_ops - helper for choosing the set of + * filesystem-wide dentry operations for the enabled features + * @sb: superblock to be configured * - * Finally, to maximize compatibility with overlayfs (which isn't compatible - * with certain dentry operations) and to avoid taking an unnecessary - * performance hit, we use custom dentry_operations for each possible - * combination rather than always installing all operations. + * Filesystems supporting casefolding and/or fscrypt can call this + * helper at mount-time to configure sb->s_d_op to best set of dentry + * operations required for the enabled features. The helper must be + * called after these have been configured, but before the root dentry + * is created. */ -void generic_set_encrypted_ci_d_ops(struct dentry *dentry) +void generic_set_sb_d_ops(struct super_block *sb) { -#ifdef CONFIG_FS_ENCRYPTION - bool needs_encrypt_ops = dentry->d_flags & DCACHE_NOKEY_NAME; -#endif #if IS_ENABLED(CONFIG_UNICODE) - bool needs_ci_ops = dentry->d_sb->s_encoding; -#endif -#if defined(CONFIG_FS_ENCRYPTION) && IS_ENABLED(CONFIG_UNICODE) - if (needs_encrypt_ops && needs_ci_ops) { - d_set_d_op(dentry, &generic_encrypted_ci_dentry_ops); + if (sb->s_encoding) { + sb->s_d_op = &generic_ci_dentry_ops; return; } #endif #ifdef CONFIG_FS_ENCRYPTION - if (needs_encrypt_ops) { - d_set_d_op(dentry, &generic_encrypted_dentry_ops); - return; - } -#endif -#if IS_ENABLED(CONFIG_UNICODE) - if (needs_ci_ops) { - d_set_d_op(dentry, &generic_ci_dentry_ops); + if (sb->s_cop) { + sb->s_d_op = &generic_encrypted_dentry_ops; return; } #endif } -EXPORT_SYMBOL(generic_set_encrypted_ci_d_ops); +EXPORT_SYMBOL(generic_set_sb_d_ops); /** * inode_maybe_inc_iversion - increments i_version diff --git a/fs/overlayfs/params.c b/fs/overlayfs/params.c index 112b4b12f825..36dcc530ac28 100644 --- a/fs/overlayfs/params.c +++ b/fs/overlayfs/params.c @@ -280,12 +280,20 @@ static int ovl_mount_dir_check(struct fs_context *fc, const struct path *path, { struct ovl_fs_context *ctx = fc->fs_private; - if (ovl_dentry_weird(path->dentry)) - return invalfc(fc, "filesystem on %s not supported", name); - if (!d_is_dir(path->dentry)) return invalfc(fc, "%s is not a directory", name); + /* + * Root dentries of case-insensitive capable filesystems might + * not have the dentry operations set, but still be incompatible + * with overlayfs. Check explicitly to prevent post-mount + * failures. + */ + if (sb_has_encoding(path->mnt->mnt_sb)) + return invalfc(fc, "case-insensitive capable filesystem on %s not supported", name); + + if (ovl_dentry_weird(path->dentry)) + return invalfc(fc, "filesystem on %s not supported", name); /* * Check whether upper path is read-only here to report failures diff --git a/fs/ubifs/dir.c b/fs/ubifs/dir.c index e413a9cf8ee3..551148de66cd 100644 --- a/fs/ubifs/dir.c +++ b/fs/ubifs/dir.c @@ -205,7 +205,6 @@ static struct dentry *ubifs_lookup(struct inode *dir, struct dentry *dentry, dbg_gen("'%pd' in dir ino %lu", dentry, dir->i_ino); err = fscrypt_prepare_lookup(dir, dentry, &nm); - generic_set_encrypted_ci_d_ops(dentry); if (err == -ENOENT) return d_splice_alias(NULL, dentry); if (err) diff --git a/fs/ubifs/super.c b/fs/ubifs/super.c index 09e270d6ed02..304646b03e99 100644 --- a/fs/ubifs/super.c +++ b/fs/ubifs/super.c @@ -2239,6 +2239,7 @@ static int ubifs_fill_super(struct super_block *sb, void *data, int silent) goto out_umount; } + generic_set_sb_d_ops(sb); sb->s_root = d_make_root(root); if (!sb->s_root) { err = -ENOMEM; diff --git a/include/linux/fs.h b/include/linux/fs.h index d15d808e8e31..30323dc70b7a 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3310,7 +3310,16 @@ extern int generic_file_fsync(struct file *, loff_t, loff_t, int); extern int generic_check_addressable(unsigned, u64); -extern void generic_set_encrypted_ci_d_ops(struct dentry *dentry); +extern void generic_set_sb_d_ops(struct super_block *sb); + +static inline bool sb_has_encoding(const struct super_block *sb) +{ +#if IS_ENABLED(CONFIG_UNICODE) + return !!sb->s_encoding; +#else + return false; +#endif +} int may_setattr(struct mnt_idmap *idmap, struct inode *inode, unsigned int ia_valid); diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 12f9e455d569..772f822dc6b8 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -192,6 +192,8 @@ struct fscrypt_operations { unsigned int *num_devs); }; +int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags); + static inline struct fscrypt_inode_info * fscrypt_get_inode_info(const struct inode *inode) { @@ -221,15 +223,29 @@ static inline bool fscrypt_needs_contents_encryption(const struct inode *inode) } /* - * When d_splice_alias() moves a directory's no-key alias to its plaintext alias - * as a result of the encryption key being added, DCACHE_NOKEY_NAME must be - * cleared. Note that we don't have to support arbitrary moves of this flag - * because fscrypt doesn't allow no-key names to be the source or target of a - * rename(). + * When d_splice_alias() moves a directory's no-key alias to its + * plaintext alias as a result of the encryption key being added, + * DCACHE_NOKEY_NAME must be cleared and there might be an opportunity + * to disable d_revalidate. Note that we don't have to support the + * inverse operation because fscrypt doesn't allow no-key names to be + * the source or target of a rename(). */ static inline void fscrypt_handle_d_move(struct dentry *dentry) { - dentry->d_flags &= ~DCACHE_NOKEY_NAME; + /* + * VFS calls fscrypt_handle_d_move even for non-fscrypt + * filesystems. + */ + if (dentry->d_flags & DCACHE_NOKEY_NAME) { + dentry->d_flags &= ~DCACHE_NOKEY_NAME; + + /* + * Other filesystem features might be handling dentry + * revalidation, in which case it cannot be disabled. + */ + if (dentry->d_op->d_revalidate == fscrypt_d_revalidate) + dentry->d_flags &= ~DCACHE_OP_REVALIDATE; + } } /** @@ -261,6 +277,35 @@ static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) return dentry->d_flags & DCACHE_NOKEY_NAME; } +static inline void fscrypt_prepare_dentry(struct dentry *dentry, + bool is_nokey_name) +{ + /* + * This code tries to only take ->d_lock when necessary to write + * to ->d_flags. We shouldn't be peeking on d_flags for + * DCACHE_OP_REVALIDATE unlocked, but in the unlikely case + * there is a race, the worst it can happen is that we fail to + * unset DCACHE_OP_REVALIDATE and pay the cost of an extra + * d_revalidate. + */ + if (is_nokey_name) { + spin_lock(&dentry->d_lock); + dentry->d_flags |= DCACHE_NOKEY_NAME; + spin_unlock(&dentry->d_lock); + } else if (dentry->d_flags & DCACHE_OP_REVALIDATE && + dentry->d_op->d_revalidate == fscrypt_d_revalidate) { + /* + * Unencrypted dentries and encrypted dentries where the + * key is available are always valid from fscrypt + * perspective. Avoid the cost of calling + * fscrypt_d_revalidate unnecessarily. + */ + spin_lock(&dentry->d_lock); + dentry->d_flags &= ~DCACHE_OP_REVALIDATE; + spin_unlock(&dentry->d_lock); + } +} + /* crypto.c */ void fscrypt_enqueue_decrypt_work(struct work_struct *); @@ -368,7 +413,6 @@ int fscrypt_fname_disk_to_usr(const struct inode *inode, bool fscrypt_match_name(const struct fscrypt_name *fname, const u8 *de_name, u32 de_name_len); u64 fscrypt_fname_siphash(const struct inode *dir, const struct qstr *name); -int fscrypt_d_revalidate(struct dentry *dentry, unsigned int flags); /* bio.c */ bool fscrypt_decrypt_bio(struct bio *bio); @@ -425,6 +469,11 @@ static inline bool fscrypt_is_nokey_name(const struct dentry *dentry) return false; } +static inline void fscrypt_prepare_dentry(struct dentry *dentry, + bool is_nokey_name) +{ +} + /* crypto.c */ static inline void fscrypt_enqueue_decrypt_work(struct work_struct *work) { @@ -982,6 +1031,9 @@ static inline int fscrypt_prepare_lookup(struct inode *dir, fname->usr_fname = &dentry->d_name; fname->disk_name.name = (unsigned char *)dentry->d_name.name; fname->disk_name.len = dentry->d_name.len; + + fscrypt_prepare_dentry(dentry, false); + return 0; } |